ppmz28

My A4 94' Z is giving me the some weird problems! I need some advice from some people that know there crap about LT-1's! First, my car is fine in the lower gears but when I get into the low end of OD it seems to jerk and shrug, or even slightly vibrate. If you hammer it, it really jerks and shrugs bad! I have also heard a light bump or knock coming from what seems to be the bottom of the engine when it does this! I feel like this is slowing my car up really really bad, I'm hoping it's nothing big. I had a friend tell me the knock( when it rarely does it) sounds like a motor mount! I don't know to much technical stuff about engines. I am trying to get around how much it might cost to fix this and how serious the problem might be! I need help bad! THANKS GUYS!!!

ftransam1

well it could be a motor mount but if your giving it gas and the car starts to shake it might just be the fuel filter. $10 fix if it is

scoobysnax83

I vote EGR valve. Tends to make the car shutter at low RPMs.

AxeGrinder30thZ

I rode in his car the other night. The car seems like it might have more than 1 thing wrong. The knocking and the "stumble" or whatever you wanna call it, doesn't seem to affect each other. The knocking sounds like a small pop at some times. I don't think it is a transmission mount, b/c I am in the process of replacing my broken one, and his noise doesn't sound as horrible as a broken tranny mount. I only guessed motor mount b/c that's the only thing I can come up with that could make that noise. As for the stumble, it could be a number of things. It might also be his fuel pump. I had to replace the fuel pump on my 87 Accord(Yes, two totally different cars, but things like a fuel pump can cause the same problems) and it kinda had the same effect. It could be possible that he is fine in the lower rpm's and mph, but if he gets on it a little bit, his pump isn't sending enough fuel...which could cause the stumble, deceleration, etc. I dunno, my vote goes to something fuel related.

scoobysnax83

Motor mount may be the noise.

But, he is saying low RPM shutter which is not fuel related. High RPM shutter is fuel/coil related. The original poster needs to clarify things a bit. Help us, so we can help you. Normally low rpm is vacuum leaks, egr valves and opti. High RPM is usually fuel/coil/ and sometimes opti. Heat is usually Coil and ICM related.

AxeGrinder30thZ

I am not sure. I wanna ride in his car again. At one point, it stumbled at a high rpm, which is why I automatically thought "fuel problem". He could also be having a vacuum leak, cause if I remember correctly, his intake elbow is slightly torn at the TB. I'm not sure how torn it is though, so I don't know the severity of what it could cause. I will try and talk with him more to get a better understanding.

AxeGrinder30thZ

Also, I think he told me when he first got the car, the opti was the first thing he changed, so I am not sure if the opti is the problem, but you never know with these cars. It's possible it could have gone out again. It's got to be either a fuel or ignition related problem.

scoobysnax83

seriously take this with the utmost seriousness, like totally....

Anyway, the intake elbow can be 210% of the problem. It may seem small, but it isn't. Disconnect the MAF connector and see if your problem goes away. If it does, then you have found it...

ppmz28

Let's see, the car seems to jerk and shutter(feels like car is letting go then holding back,repeat) in the lower rpm's but when you get into the higher rpm's of 4 while hammered the car wants to take forever it seems to shift and jerk while getting there! The problem seems to be getting worse and I have no idea what it is! Thanks!

AxeGrinder30thZ

What's this all about? Just trying to help man.

Check your PM box, I sent that PM before you said that, just thought I would let you know.

shoebox

Sounds like it is missing. It will be more noticeable when you are in higher gears and the rpms are low. Check plugs and wires.

scoobysnax83

I guess that came out wrong. But I meant nothing by it. Just trying to grab your attention. It was more like a light bulb going on in my head and not being able to express my thoughts.

ppmz28

Just to add, my car has been put on a diagnostics at several places and no bad feedback!!!!THANKS!!

Laymaster

check your plugs/wires. if one of the plugs is black, replace it and the wire as well. when i burnt a wire, the plug stopped firing and i had the same exact problem.